Grease composition



United States Patent T 3,192,161 GREASE COMPOSITION Max J. Wisotsky, University Park, Pa., and Norman R. Odell, Wappingers Falls, N.Y., assignors to Texaco Inc, New York, N.Y., a corporation of Delaware No Drawing. Filed Dec. 14, 1962, Ser. No. 244,568 a 13 Claims. (Cl. 252-42.7)

This invention relates to a lubricating grease composition and to a novel class of thickening agents therefor. More particularly, the present invention relates to a lubricating grease composition thickened to a grease consistency with a particular class of metal chelates of salicylidene-amiuobenzene Schiff bases.

We have found that certain copper and nickel chelates of N-salicylideneamino-substituted benzenes form stable grease compositions having excellent lubricating properties in lubricating oils, such as mineral oils and synthetic oils including silicone polymer oils, ester oils and diester oils.

The copper and nickel chelates of the N-salicylideneamino substituted benzene Schiff bases which are employed as grease thickening agents in the present invention are represented by the general formula:

wherein R is a member selected from the group consisting of o-hydroxy and p-nitro, preferably o-hydroxy, and wherein M is a member selected from the group consisting of nickel and copper, preferably nickel, and wherein, when M is copper, R is o-hydroxy.

Particularly suitable N-salicylideneamino substituted benzene Schifi base compounds to prepare the copper or nickel chelate thickening agents include N-salicylideneamino o-hydroxybenzene and N-salicylideneamino-pnitrobenzene. The particular metal chelating N-salicylideneamino substituted Schiif base compounds employed in the lubricating greases of the present invention as the thickening agents include the nickel and copper chelates of N-salicylidene-amino-o-hydroxybenzene, and the nickel chelate of N-salicylideneamino-p-nitrobenzene. It is indeed surprising that these particular chelates are effective thickening agents in lubricating greases when other chelate compounds, such as the nickel chelate of N-salicylideneamino-o-methylbenzene, the copper chelate of N-salicylideneamino-m-hydroxybenzene, and the copper chelate of N-salicylideneamino-p-nitrobenzene are not satisfactory grease thickening agents in lubricating base oils.

The grease compositions of the present invention comprise a lubricating base oil having a viscosity in the lubrieating oil viscosity range, containing a copper or nickel chelate of N-salicylideneamino-o-hydroxybenzene or the nickel chelate of N-salicylideneamino-p-nitrobenzene, in an amount suflicient to thicken said baseoil to a grease consistency. In general, the composition contains from about 51 00 90 percent of lubricating base oil and from 10 to 49 percent of the metal chelate, based on the weight of the composition. The grease compositions of the invention usually also contain from 0.5 to about by Weight of a grease corrosion inhibitor and, in addition, may contain from about 0.5 to 5% by weight of an amine oxidation inhibitor. I

As is understood in the grease art, the grease compositions may additionally contain minor amounts of con- 3,192,151 Patented June 29, 1965 ventional lubricity agents, coloring materials, extreme pressure agents, and the like, including combinations of these materials.

A preferred lubricating grease composition comprises from about 53 to 78% by weight of a synthetic silicone polymer oil having a viscosity in the lubricating oil viscosity range, from 20 to 45% by weight of nickel chelate of N-salicylideneamino-o-hydroxybenzene, 1.0% of diphenyl-para-diphenylene diamine as an oxidation inhibitor, and 1.0% N-cocoyl sarcosine as a corrosion inhibitor, wherein cocoyl represents coconut oil acids.

Satisfactory aryl amine oxidation inhibitors include diphenyl amine, phenyl alpha-naphthylarnine, paraphenylene diamine, and N,N-diphenyl-para-phenylene-diamine.

Satisfactory corrosion inhibitors include lead naphthenate and the sarcosines including the N-acyl sarcosines containing from 8 to about 20 carbon atoms in the acyl group such as N-cocoylsarcosine, N-laurylsarcosine and N-stearyl-sarcosine, wherein cocoyl represents coconut oil acids.

The lubricating base oil may be a silicone polymer base fluid. The silicone polymer base fluids used to form the greases of the present invention are compounds having the general formula:

wherein R, R R R R and R are methyl, phenyl or chlorinated phenyl groups, preferably at least about 35% thereof being methyl groups and with sufficient chlorinated phenyl groups to give a chlorine content of at least about 3% by weight to the polymer and wherein n is an integer of sufficient size to give a polymer having a viscosity in the lubricating oil viscosity range. The preferred silicone oils are those having a viscosity of from about to 600 seconds Saybolt Universal at 100 F. and contain about 4 to 12 percent by weight of chlorine. A particularly suitable silicone polymer material is the commercial product sold under the trade name Versilube F-SO, having an average molecular weight of about 3,233, a viscosity of about to 280 seconds Saybolt Universal at 100 F., and containing about 33.6% silica and 7.18% of chlorine by weight. Another suitable silicone polymer base fiuidsold under the trade name of Dow F-60, can be used in the grease compositions of the invention.

The methylchlorophenyl silicone polymer oil can be employed as the sole oil component, or it may be employed in admixture with minor amounts of other oils, such as mineral oils, and particularly other synthetic oils, such as polyethers, polyglycols, diesters, polyesters or mixtures of such oils.

The aliphatic ester type base fluids for use in the grease compositions include the diesters of primary alcohols and aliphatic dicarboxylic acids. The dicarboxylic acid component usually contains from 6 to 12 carbon atoms, but glutaric and succinic acids are also included. From the standpoint of cost and availability, the preferred acids are adipic, sebacic, and azelaic. The primary aliphatic alcohol used to form the diester base fluid usually contains at least 4 carbon atoms and may contain 30 or more carbon atoms. C to C alcohols are most commonly used. Specific examples of the dialkyl esters of aliphatic dicarboxylic acids which are the preferred base fluid bases for use in the grease composition of the invention are as follows: dibutyl azelate, di-Z-ethylhexyl azelate, dilauryl azelate, di-tridecyl .azelate, dihexyl sebacate, di- Z-ethylhexyl sebacate, dihexadecyl sebacate, di-2-ethy1- hexyl adipate, and diisooctyl adipate. A particularly tively and x is an integer from 1 to 5.

The aliphaticxdiester base oil or the synthetic ester base oil can be employed as the sole oil component in the grease compositions of this invention. Moreover, these oils can be employed in admixture with minor amounts of other oils, including mineral oils, and other synthetic oils, such as a silicone polymer oil, a polyether oil, a polyglycol oil, a polyester oil, or mixtures of .said oils;

Suitable mineral oils for use as the base oil in the grease compositions of the invention include refined paraffinic and naphthenic oils, particularly refined paraflin oils having viscosities in the range of from about 100 to 600 seconds Saybolt Universal at 100 F. The mineral oil can be used as the sole oil component or in admixture with other oils including mineral oils or synthetic oils such as a silicone polymer oil, a polyether oil, a polyglycol oil, a polyester oil or mixtures of said oils.

Specific details for the preparation of the nickel and copper chelates of N-salicylidcneamino-o-hydroxy and pnitro-substituted benzenes will be readily apparent from the following examples.

EXAMPLE A v EXAMPLE B Nickel-N-salicylideneamino-p-nitrobenzene was prepared in a similar maner from nickelous acetate tetrahydrate and the Schiif base prepared from salicylaldehyde and p-nitroaniline in a mixed methanol-dioxane solvent.

EXAMPLE C The copper chelate of N-salicylideneamino-o-hydroxybenzene was preparedfrom a reaction mixture of 210 parts of cupric acetate monohydrate, 270 parts of salicylaldehyde and 218 parts of o-aminophenol in a hot mixed water-methanol solvent. The hot mixture was stirred for 30 minutes, then heated on a hot plate for 1 hour at a temperature of about 140-149 F. The green reac tion product was obtained in 56.5% yield.

EXAMPLE D i The copper chelate of N-salicylideneamino-p-nitro-ben-. zene was prepared in a manner similar to that described, in Example B above using the mixed water-methanol solvent of Example C above. The red-brown chelate had a melting point of 300 C.+ (literature 313 C'.) and was obtained in 85.3% yield.

' parts of Sarkosyl LC corrosion inhibitor.

4 EXAMPLE 1 A grease composition was prepared in the following manner. A nickel chelate of N-salicylideneamino-o-hydroxybenzene, pre ared in a manner similar to the chelate of Example A above, in 1,325 parts of an acetone slurry (206 parts of nickel chelate), 140 parts of a synthetic ester oil obtained by reacting sebacic acid, 1,3-hexanediol and 2-ethylhexanol in about 2: 1 :2 ratio, respectively, and consisting predominantly ofthe compound and parts of a refined parafiin distillate oil mineral oil A having a 29.7 API gravity, a viscosity at F. of 350 SSU, and a neutralization number 0.03. The reactants were admixed and heated for two hours at 220-230 F. with stirring, then for one hour at 300 F. Heat was discontinued and therewas added to the hot mixture 253 parts of the synthetic ester oil described above, 10.5 parts of the mineral oil A, 7.0 parts of diphenyl-p-phenyenediamine oxidation inhibitor and 7.0 The resultant hot mixture was milled for two passes in a Premier Colloid Mill having a rotor-stator clearance of 0.008 inch. The grease was a green'colored buttery grease. Inspection tests and percentage composition of the grease are shown in tables below.

EXAMPLE 2 A grease composition was preparedin the following manner. A nickel chelate of N-salicylideneamino-o-hydroxybenzene was prepared in a manner similar to the nickel chelate of Example A above, A chelate slurry in an amount of 849 parts, containing 218 parts of the nickel chelate and 631 parts of acetone was added to 327 parts of a silicone polymer oil, Versilube F-50, and mixed and heated to ZOO-210 F. for 3 hours. At this temperature the acetone solventiwas removed and 255 parts of Versilube F-SO added thereto. The resultant admixture was passed three times through the Premier Colloid Mill with a rotor-stator clearance of 0.002 inch. The product was .a green colored buttery grease. Inspection tests andcompositions of the grease are set forth in the tables below.

EXAMPLE 3 A grease composition was prepared by blending about 1158 parts (voL) of a water-methanol-denatured alcohol solvent mixture containing 13.3 parts (wt.) of thecopper chelate of N-salicylideneamino-o-hydroxybenzene prepared in amanner similarto Example C above with 80 parts of mineral oil B, a refined paraflin oil having an API gravity of 20.1", a viscosity at 100 F. of 316 SSU, and a neutralization number of 0.05. The blended mixture was stirred and heated to a temperature of approximately 200 F. and maintained thereat to remove the solvent therefrom by evaporation. After removal of the solvent there was added to the heated mixture 40 parts of oil and the resultant blend was passed once through the Another grease composition was prepared in a manner similar to Examples 1-3 above. The composition and inspection tests on this grease composition are shown in the tables below.

. Table I sets forth the percentage compositions of the grease compositions. Table II sets forth the results of; tests performedon the grease compositions of Table I.

Table 1 Composition, weight percent Example 1 Example 2 Example 3 Example 4 Example 5 Silicone polymer oil F-50 72.8 53. 2 63.6 Synthetic ester oil AP52-.- 55. 0 Mineral oil A 12. 6 Mineral oil B 90 Sarkosyl LC 1. 0 Diphenyl p-phenylenediamine. 1. 0 Nickel SA 0(OH) benzene* 30. 4 27. 2 Nickel SA p(NO) benzene* 46. 8 Copper SA 0(OH) benzene- 10 36. 4

SA=N-salicylideneamino.

Table 11 Example 1 Example 2 Example 3 Example 4 Example 5 Appearance Green Buttery Smooth Buttery Smooth Buttery ASTM penetration:

Unworked 290 257 317 324 257 Worked:

60 strokes 302 322 339 300 294 100,000 strokes 302 260 Dynamic water resistance, percent loss. 5 0 Water absorption, percent loss- 5 Penetration on emulsion 278 305 Dropping point, "F 500+ 500+ Bomb oxidation, p.s.i. 100 hr 210 F 4 250 F 2 4 Oil separation, 30 hrs, 450 F., percent ss 4.0 2. 3 3.1 High temperature performance, hrs. at

450 200 Oil evaporation, 22 hrs., 350 F., percent loss 4. 39 3. 62 1. 08 Copper strip corrosion, 24 hrs 212 F.,

r ing Pass-clean Pass-clean Storage stability penetration,* unworked (Worked):

Original 294 257 (322) 268 (272) 3 months 208 (311) 193 (272) Converted to ASTM trom $4 cone, worker used.

Inspection of the data in Table II above indicates that the grease compositions of the present invention containing the nickel and copper chelates of N-salicylidencamino-o-hydroxybenzene and nickel chelate of N-salicylidene-amino-p-nitrobenzene as thickening agents for silicone polymer, mineral oil and ester base oils are satisfactory greases.

The grease composition of Example 1 above was a buttery No. 1 grade grease possessing a 500 F.+ dropping point and an excellent shear stability. The water resistance, oxidation resistance, Water absorption, oil separation and oil evaporation properties of the composition were good.

The grease composition of Example 2 above Was a smooth, green No. 1 grade grease having a 500 F.+ dropping point, good shear stability, water resistance and water absorption characteristics. The results of the oil separation, oil evaporation, bomb oxidation and copper corrosion tests were also good. Satisfactory results were also obtained With this grease in the High Temperature Performance Test in which the grease performed for 200 hours at the high temperature (450 F.) of this test.

The grease composition of Example 3 was also a high dropping point, (500 F.+) smooth grease that performed satisfactorily in tests.

The grease composition of Example 4 above was a smooth No. 0 grease, possessing a high dropping point and low oil separation values. A satisfactory oil evaporation value was obtained With this grease.

The grease composition of Example 5 above was a smooth No. 1 grade grease product with a relatively high (500 F.) dropping point temperature. The grease exhibited good shear stability, water resistance and Water absorption characteristics. The smooth texture and lOW oil evaporation values are particularly good. Oil separation, bomb oxidation and copper corrosion test results were likewise good.

Additional experiments Were conducted to evaluate similar metal chelates of N-salicylideneamino substituted benzenes in various lubricating oils but the results were unsatisfactory.

The nickel chelate of N-salicylideneamino-o-methylbenzene in an amount of 34.6% when blended with silicone polymer oil, Versilube F-50, in a manner similar to that described hereinabove resulted in a fluid system unsuitable as a grease. Similarly, using 39.5% of copper chelate of N-salicylideneamino-m-hydroxybenzene in sili cone polymer oil. Versilube F-SO, also produced an unacceptable fluid system.

The copper chelate of N-salicylideneamino-p-nitrobenzone in amounts of 37.5 and 47.3% in Versilube F-SO, respectively, yielded greases having very high unworked penetration values of the order of 384 and 400+, respec tively. These test values demonstrate that the resultant blends are unsatisfactory greases because of their soft consistencies. These greases did not harden even after shearing or after absorption of water.

These tests serve to demonstrate the specificity of the particular nickel and copper N-salicylideneamino-o-hydroxybenzene and nickel N-salicylideneamino-p-nitrobenzone chelates as thickening agents for lubricating greases. Obviously, many modifications and variations of the invention, as hereinbefore set forth, may be made without departing from the spirit and scope thereof, and therefor only such limitations should be imposed as are indicated in the appended claims.

We claim:

1. A grease composition comprising a lubricating base oil having a viscosity in the lubricating oil viscosity range containing a compound selected from the group consisting of the copper and nickel chelates of N-salicylideneamino-o-hydroxybenzene and the nickel chelates of N-salicylideneamino-p-nitrobcnzene in an amount suflicient to thicken said base oil to a grease consistency.

77v 2. A grease composition as claimed in claim 1 wherein the. lubricating base oil comprises from about 51 to 90 percent by weight and the metal chelate thickening agent comprises from about to 49 percent by weight, based on the weight of the composition.

3. A grease composition as claimed in claim 1 wherein the thickening agent is the nickel chelate of N saIicyIi- 7 A grease composition as claimed in claim 6 wherein. the silicone polymer oil is a methylchlorophenyl silicone t polymer oil having a viscosity in the range or" from about 180 to about 280 seconds, Saybolt Universal at 100 F; 8.- A grease composition as claimed in claim 1 wherein the lubricating base oil-is a refined parafiin distillate mineral oil. a a

9.. A grease composition as claimed in claim 1 wherein the lubricating base oil is a synthetic ester oil.

10. A grease composition as claimed in claim 1 wherein the lubricating base oil comprises an admixture of about 5 5 by weight of methylchlorophenylsilicone polymer oil 8 and about 12.6% by weight of a refined parafiin distillate oil.

11.1 A grease composition comprising 53 to 78'percent by weight of a methylchlorophenyl? silicone polymer oil having a viscosity in the lubricating oil viscosity range; thickened to a grease consistency with from 20 to percent by weight of a nickel chelate of N-salicylideneaminoo-hydroxybenzene. and containing one percent by weight of an amine oxidation inhibitor, and about one percent by weight of a sarcosine corrosion inhibitor.

12. A grease composition as claimed in claim 11 wherein the amine oxidationinhibitor is diphenyl+para phenylenediamine.

13. A grease composition as claimed in claim 11 wherein the sarcosine corrosion inhibitoris N-cocoyl sarcosine.

Reterences Cited by the Examiner UNITED STATES PATENTS 3/61 Gash 44-7 OTHER REFERENCES DANIEL E. WYMAN, Primary Examiner. 

1. A GREASE COMPOSITION COMPRISING A LUBRICATING BASE OIL HAVING A VISCOSITY IN THE LUBRICATING OIL VISCOSITY RANGE CONTAINING A COMPOUND SELECTED FROM THE GROUP CONSISTING OF THE COPPER AND NICKEL CHELATES OF N-SALICYLIDENEAMINO-O-HYDROXYBENZENE AND THE NICKEL CHELATES OF N-SALICYLIDENEAMINO-P-NITROBENZENE IN AN AMOUNT SUFFICIENT TO THICKEN SAID BASE OIL TO A GREASE CONSISTENCY. 